Seraph of the End: Vampire Reign

Seraph of the End: Vampire Reign is a 2012 manga.

One day, a mysterious virus that infected humans appeared and killed every human who was infected over the age of 13. At the same, time, vampires came out of the shadows and enslaved as much of mankind as possible, using children as their source of food. Yuuchirou Byakuya was one of them, and tried to escape from the vampires's territory along with other children he considered family, but all but him were apparently killed. Consumed by the guilt of having left his best friend Mikaela to die, Yuuchirou swears vengeance, but things will be more complicated than what he thinks...

Written by Takaya Kagami, Art by Yamato Yamamoto. Serialied on Shueisha's Jump SQ.

Tropes used in Seraph of the End: Vampire Reign include:

Battle in the Center of the Mind: So someone can use a Cursed Gear, he must defeat the demon in a battle fought inside the wielder's mind, where the demon can use the wielder's own memories against him.
Cleavage Window: Averted for Krul because she is, well, flat.
Dude Looks Like a Lady
- Asuramaru's dress, voice and young appearance makes it difficult to guess its gender at first.
- Yuichi's hairstyle, petite build, and sweet personality makes him, ahn, look pretty feminine.
Fangs Are Evil: The vampires, obviously.
Foil: Shinoa, in classic Sancho Panza and Dom Quixote's fashion, is realistic, more smart and sarcastic than the main hero of the story.
Idiot Hero: Yuu seems to be obsessed with doing everything he wants to do quickly, so quickly he puts himself at risk.
Living Weapon: All Cursed Gears have demons living inside them.
Red Eyes, Take Warning: Some vampires have red eyes.
Older Than They Look: All vampires since they are immortal undead beings who only look human, after all, but Krul especially looks like a child/early preteen but acts and have the position of an adult in her society.
Token Loli: Krul has a petite body and appearance, with her outfit designed to partially expose this.